Electric cells are known in which the positive electrode includes a compound here referred to as an insertion or intercalation compound in which the negative active material is inserted during discharge, said negative active material generally being an alkali metal. Such compounds are, for example chalcogenides such as titanium sulphides or nickel phosphosulphide, mixed sulphides e.g. of bismuth or of lead or of copper, or oxyhalides of transition metals, e.g. FeOCl.
Such electric cells may undergo a high number of charge-discharge cycles and they are also suitable for delivering a high energy density. With a view to improving further the performances of electric cells of this type, the Applicant has therefore sought compounds which can be used as active material for the positive electrode.
The Applicant has observed that some compounds which have a thiospinel or olivine structure are particularly adequate for dynamically intercalating the negative active material and for enabling the realization electric cells which are rechargeable and have excellent performance.
Such an electric cell may be manufactured optionally either in the charged or in the discharged state.